1. Technical Field
The present disclosure relates to systems and methods for providing energy to biological tissue and, more particularly, to an ultrasonic dissection system having frequency shifting and multifrequency operating modes, and methods of use therefor.
2. Background of Related Art
Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryogenic, thermal, laser, etc.) are applied to tissue to achieve a desired result. Ultrasonic energy may be delivered to tissue using a surgical probe that includes a transducer coupled with an end effector, and configured to deliver ultrasonic energy to tissue.
The use of ultrasonic energy in surgical procedures is known to those skilled in the art to be a valuable resource for cutting and fragmenting tissue of a patient. Most of these apparatus incorporate a sinusoidal driving signal which causes the mechanical tip to vibrate at a selected frequency, usually in the range of 20 KHz to 60 KHz.
The benefits associated with the use of ultrasonic energy powered devices, and in particular, ultrasonic instruments for surgical use, are known. For example, the use of an ultrasonic generator in conjunction with a surgical scalpel facilitates faster and easier cutting of organic tissue while accelerating coagulation. Improved cutting may result from increased body tissue-to-scalpel contact caused by the high frequency of vibration of the scalpel blade in relation to body tissue. Improved coagulation may result from heat generated by contact between the high frequency vibrations of a scalpel blade and body tissue.
Ultrasonic instruments may include a variety of end effectors (e.g., cutting blades, shears, hook, ball, forceps, etc.) adapted for specific medical procedures. The ultrasonic end effector is disposed at a distal end of the ultrasonic instrument. These ultrasonic instruments are primarily used in a variety of medical procedures including open surgical procedures, luminal procedures and endoscopic procedures.
It is known that at the lower end of the preferred frequency spectrum, e.g., 20 KHz to 40 KHz, larger tip displacements are possible. It is also known that larger tip displacements provide a better tissue cutting effect than small tip displacements. Ultrasonic energy at the high end of the preferred frequency spectrum, e.g., 40 KHz to 60 KHz, can have a more hemostatic effect. This is due in part to the increased absorption of higher frequency energy by tissue. However, larger tip displacements are not feasible at these higher frequencies. Therefore, devices which operate in this realm may have reduced tissue cutting performance.